Blank from which a customized prosthetic part can be machined

ABSTRACT

A blank used for machining customized prosthetic components is provided which includes a prefabricated seating surface, normally shaped as an anti-rotation device, used to seat the component in the corresponding implanted, or natural, surface in the patient&#39;s body. Prosthetic components need to be custom manufactured because each patient presents a different need, however, the standardized shape of seating surfaces allows for these to be machined in large scale, without affecting the quality of the treatment the patient receives. Once the customized manufacturing has been completed around the seating surface, the part requires no further machining and is ready to be used.

FIELD OF THE INVENTION

The present invention relates to a blank used to manufacture customizedprosthetic components, more particularly, abutments of dental prostheticreplacements.

BACKGROUND OF THE INVENTION

The present invention relates to a blank that facilitates the rapid andeconomical production of dental prosthetic components. Dental prostheticcomponents, normally made from ceramic or metallic materials, are usedto functionally substitute a part of a patient's dentition. There arethree major components used in a complete prosthetic restoration, asubstitute for the tooth's root (called a fixture), a substitute for atooth's internal structure (called an abutment), and a cosmeticsubstitute, which replaces the tooth's appearance. Some patient's mayneed only cosmetic substitutes while others need a full replacement.

Normally, when a patient needs a prosthetic replacement, severalsurgical and laboratory steps must be completed before the actualreplacement is ready to be installed. These steps range from installinganchors into the patient's bones to fabricating the prostheticreplacement itself. One thing that must be understood is that regardlessof the kind of treatment the patient is undergoing, time is the crucialelement. The longer it takes to properly treat a medical condition, thefurther the scenario deteriorates, thus the bigger the problem thatneeds resolving. Recent developments in the art have allowed forcosmetic substitutes (namely crowns, bridges, or inlays) to bemanufactured by CAD/CAM devices, directly in the dentist's office(sometimes referred to as chair-side systems), thus shortening the timebetween a patient's admittance to his release. However helpful, cosmeticreplacements are seldom used alone, and treatments that require otherprosthetic components must still endure the delays involved infabricating the remaining components. The main reason current chair-sideCAD/CAM systems cannot manufacture abutments or fixtures is the highdegree of precision required to manufacture the connecting elements,which join prosthetic components together ensuring their properalignment and securing them form rotating once installed. Since mostchair-side systems cannot achieve said high degree of precision duringmilling, these machines cannot produce abutments or fixtures using theircurrent blanks. The present invention pre-integrates the connectingelement into the design of the blank that will be milled, thus helpingto further reduce the time needed to treat a patient, once it allows forthe remaining dental prosthetic components to be manufactured inside thedental office, often using the same CAD/CAM equipment already applied inmaking the cosmetic parts.

SUMMARY OF THE INVENTION

The present invention allows for the fast and economical production ofcustomized dental prosthetic components, by providing a blank withpre-fabricated connecting elements. Since connecting elements havestandardized dimensions with few discrete variations, they can be easilymass-produced into the blanks. By pre-fabricating the connecting elementinto the blank's design, all that remains to be done in the dentaloffice is to custom form the outer part of the blank according to thespecific need of the patient. This operation is much simpler, and can beachieved with most of the currently available CAD/CAM systems for thedental office. In this sense, a blank used for machining customizedprosthetic components is provided which includes a prefabricated seatingsurface, normally shaped as an anti-rotation device, used to seat thecomponent in the corresponding implanted, or natural, surface in thepatient's body.

The connecting element of a prosthetic component is the geometry used toalign and lock the element from rotating relative to a joined secondprosthetic component, these are often presented as hexagonal connectorsor Morse Cones, but other geometries may also be applied. For example,fixtures (which are installed into the patient's bone) may have anhexagonal connecting element and a corresponding abutment (the part thatreplicates the tooth's internal structure) would have the correspondinghexagonal connecting element, when coupled together, the joinedconnecting elements from both parts would prevent the parts fromrotating thus maintaining alignment between the parts. Depending on thedental reconstruction, parts with more than one connecting element maybe required. The present invention also resolves this situation becausethe blank can have more than one connecting element. In the case ofmultiple connecting elements, a template would have to be used duringthe surgical procedure (installation of the fixture) to ensure properalignment later on.

In order to facilitate the milling operation of a prosthetic component,the blank must also include a support geometry, used to fasten the blankin the milling machine that will perform the customization. This supportgeometry may range from a simple elongation of the stub, to more complexone-step-locking designs. An example of one-step-locking design would bea Morse-Cone, where the geometry forces the part to lock once it's putinto place.

Finally, the blank must include the access paths for fastening screws,which will be used later to secure the different prosthetic componentstogether.

BRIEF DESCRIPTION OF THE DRAWINGS

Briefly, FIGS. 1, 2, and 3 show current state of the art on blanks formilling dental crowns, bridges or inlays; FIG. 4 shows the supportingelement from related U.S. Pat. No. 6,224,371, joined with the blankproposed in this invention; finally FIGS. 5-10 show variations of thepresent invention.

FIG. 1: resents the supporting stub currently used to fasten blanks inmilling machines;

FIG. 2: Shows the block from which the actual final crown, bridge, orinlay will be cut is shown cemented to the supporting stub shown in FIG.1;

FIG. 3: Presents a variation of the current state of the art where thesupporting stub already is made from the material from which the finalpart will be cut;

FIG. 4: Shows the support stub containing the connecting elementpresented in related U.S. Pat. No. 6,224,371, along with the blankcontaining the connecting element presented in this invention;

FIG. 5: Illustrates a variation of the present invention where the blankcontaining the connecting element is cemented to the supporting stub;

FIG. 6: Presents a variation of the present invention where the blankcontaining the connecting element includes the support geometry;

FIGS. 7 and 8: Show variations of FIGS. 5 and 6, where the connectingelements are pre-fabricated in a different face of the blank;

FIG. 9: Schematically represents a prosthetic component cut from theblank proposed in the present invention;

FIG. 10: Illustrates the blank from the present invention with more thanone connecting element, and a schematic representation of a prostheticcomponent to be cut from the blank.

DETAILED DESCRIPTION OF THE INVENTION

Improvements in the art include allowing for final parts to be cut at alow cost, directly where the part will be used. The pre-fabrication ofconnecting elements (5) into the blanks (FIGS. 4 to 10) exclude the needfor any future milling on the part, once customization is done, thussimplifying the build process for a prosthetic component.

When designing the blank, the critical characteristic is the connectingelement (5), other shape defaults, such as outer shape, aren't ascritical and can be provided in such a way that best suit's the user'srequirements. The general orientation between blank and connectingelements, that is the direction (or surface) where it occurs on theblank is not a factor in fixating the blank to the milling machine. Theblank proposed in this invention can be fastened to the milling machineby any of its surfaces, and, similarly, the connecting element canappear pre-fabricated in any of the blank's surfaces.

FIG. 4 shows the support stub (10) containing the connecting elementpresented in related U.S. Pat. No. 6,224,371, along with the blank (6)containing the connecting element (5) and access path (7) for fasteningscrew (11) presented in this invention.

FIG. 5 Presents a variation of the present invention where the blank (6)containing the connecting element (5) and access path for screws (7) iscemented (8) to a supporting stub (9) similar to (1).

FIG. 6 Presents a variation of the present invention where the blank (6)containing the connecting element (5) and access path for screws (7)includes the support geometry (9).

FIGS. 7 and 8, Present variations of FIGS. 5 and 6, where the connectingelements (5) are pre-fabricated in a different face of the blank.Moërmann et al. described in U.S. Pat. No. 4,615,678 a blank, shown inFIG. 2, that allowed the milling of prosthetic components on location,that blank, however included two parts that where cemented (2) together,a block (3) from which the final piece would be cut, and a supportingstub (1), shown in FIG. 1. A variant type blank (4) (shown in FIG. 3)composed exclusively of one kind of material, is used in some CAD/CAMsystems (an example of which would be Cynovad) to fabricate crowns andbridges, but doesn't allow abutments to be milled because it lacks thepresence of a connecting element. Other examples available in industry,generally present the same ability to perform inlays, crowns andbridges, but lack the expansion potential to abutments because they lackthe connecting element.

The improvement in the art presented by this invention, allows forCAD/CAM machines, currently limited in their ability to manufactureprosthetic components, to expand their universe of possibilities intothe realm of abutments and fixtures.

FIG. 9 Schematically represents a prosthetic component (12) cut from theblank (6) proposed in the present invention. The blank is attached tothe milling machine through the support geometry (9) so that itssecurely fastened and can be properly cut. Notice the presence of thepre-fabricated connecting element (5) at the base of the finalized part,along with access path (7) for the screw that will later be used tofasten this component to other prosthetic parts.

FIG. 10, presents the blank (6) from the present invention with morethan one connecting element (5), and a schematic representation of aprosthetic component (13) to be cut from the blank (6). Once again,notice the presence on the pre-fabricated connecting elements (5) andscrew paths (7) in the final part (13). This variant of the proposedblank also contains a support geometry (9) so that it can be properlyattached to the milling machine.

Whereas co-owned U.S. Pat. No. 6,224,371 proposes a supporting device,the present invention relates to the entire blank, part which willactually be cut. This blank (6) may be composed of different kinds ofbiocompatible materials, normally Titanium or ceramic type materials areused, Biomaterials (including human or bovine Demineralized Freeze BoneDry Allograft (DFBDA); human or bovine Freeze Bone Dry Allograft (FBDA);or, synthetic or coral hydroxyapatite, amongst others currently beingdeveloped) may also be applied, but ultimately the material that shouldbe used is the one that best suits the patients' need.

1-7. (canceled)
 8. A method for forming a prosthetic component from ablank, comprising: providing a blank body, a portion of an outer surfaceof the blank body forming a pre-fabricated seating surface, thepre-fabricated seating surface including at least one anti-rotationelement, the blank body including a first support portion and a secondcomponent portion, wherein the first and second portions are integrallyformed and positioned adjacent one another, the blank body being madefrom a biocompatible material; supporting the first support portion ofthe blank body; and forming the second component portion of the blankbody into a prosthetic component.
 9. The method of claim 8, whereinsupporting the first support portion includes supporting the firstsupport portion with a portion of a milling machine.
 10. The method ofclaim 8, wherein forming the second component portion includes formingusing a CAD/CAM system.
 11. The method of claim 10, wherein the CAD/CAMsystem is a chair-side CAD/CAM system in a dental office.